Pressure Washer Modifications
Author: Tom Eddleman
Revised: August 03, 2005
After trial and error this works. Nicholas Mazza ordered the parts and modified a pressure washer with them.
Most sandcarvers quickly discover the advantages of using a pressure washer
for developing photo resist. If you get a low cost Karcher or the
equivalent pressure washer it will run somewhere around $100, but the wand that
comes with it is way too long to washout resist with, so modifications have to
here's a list of what you need:
The Karcher pressure washers have a 22mm male thread outlet
The Northern Hose P/N 32090 hose ($16.99) has 22mm female thread on both ends
One end connects to the pressure washer outlet and the other to a
Northern P/N 22321 adapter ($4.99) that is 22mm male thread on one end and 3/8 NPT female thread on the other end.
The female thread part of the adapter screws over the Northern P/N 2296 nipple ($2.99) that is 3/8 NPT male thread on both ends.
That nipple screws into the Northern P/N 227770 ($14.99) pistol grip gun inlet.
A 1/4"x 3" NPT nipple (hardware store) screws into the outlet on the gun and a Northern P/N 2234 quick coupler ($5.99) screws onto that nipple. A Northern P/N 230340 ($6.99) 40 degree nozzle connects with that quick coupler.
Northern Hose P/N 32090 ($16.99)
adapter P/N 22321 ($4.99)
nipple P/N 2296 ($2.99)
pistol grip gun P/N 227770 ($14.99)
quick coupler P/N 2234 ($5.99)
40 degree nozzle P/N 230340 ($6.99)
Hardware Store: nipple 1/4"x 3" NPT
This should get you going. Home Depot, Lowe's, etc. may have the best deal on
the pressure washer.
On operating temperature: do not operate the washer above 105F, since the
Buna N seals will be destroyed at higher temperatures. You can
guesstimate the temperature, or buy a Radio Shack remote thermometer with probe
for less than $20. The fancier models also include humidity readout with
memory, for not much more.
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